Array formats

A table has rows and columns; an array has dimensions. A dense array fills every cell of a grid, like an image or a climate model’s lattice, while a sparse array stores only the cells that exist, keyed by their coordinates. TileDB groups cells into fixed-size tiles and stores each attribute separately, so a read fetches only the tiles and attributes a slice touches.

Writes never edit old files. Each one creates an immutable fragment named after the time range it covers, which suits object stores such as S3 and lets readers open an array as it was at an earlier time.